Cabal. P.I. Frank Johnson Mystery Series, #36

After repulsing three violent attacks by an unidentified adversary, Frank determines that he is facing a "cabal" bent on destroying him. Despite placing his paying clients' cases on hold while he investigates it full-time, he can't pin down who they are. Or why they targeted him to kill. He teams up with his ally, mobster don Maggot Nose, who has his own reasons for dismantling the cabal. However, they always seem to be one step behind its elusive maneuvers.
Frank realizes that if he doesn't see it through, the pernicious cabal will return to finish its hit job on him. Remaining on high alert, he is prepared to defend against its next assault. As Frank's investigation expands, the arrogant, racist, and combative new town sheriff comes under suspicion. Frank also speculates if the Blue Cheer, a vicious religious cult he tangled with decades earlier in mountainous West Virginia, has returned to exact its murderous vengeance on him.
The hot pursuit leads them to a deserted, tacky mansion on a storm-blasted knoll in rural Virginia. The first clues Frank discovers prove that the cabal stayed there and has put him in its crosshairs. Once again, the cabal slips away before he is able to confront it, leaving him frustrated and angry. He knows it's lurking just out of sight, waiting for the right moment to pounce, and he needs to strike first if he wants to win.